Lubricant supply mechanism for an internal combustion engine

ABSTRACT

In a lubricant supply mechanism for an internal combustion engine with an oil receiving case arranged under a crankcase, two chambers are constructed for exhausted oil. A first oil pump suctions lubricant from a first chamber and supplies the lubricant to a consumer, such as, for example, a crankshaft bearing or cam shaft bearing of the internal combustion engine. A second oil pump suctions the lubricant off from a second chamber and supplies the lubricant to the first chamber by way of an oil cooler for cooling the lubricant. The oil cooler defines part of a circuit providing for oil circulation produced by the second oil pump.

This application claims the priority of prior German application 10 2005 012 073.3, filed Mar. 16, 2005, the entire disclosure of which is incorporated herein by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention concerns a lubricant supply mechanism for an internal combustion engine including an oil receiving pan arranged under a crank case and constructed with first and second chambers designed for receiving exhausted oil. The mechanism further includes a first oil pump by which the oil is suctioned from the first chamber and provided to a consumer of the internal combustion engine, a second oil pump by which the oil is suctioned from the second chamber and provided to the first chamber, and an oil cooler for cooling the oil.

German publication DE 101 59 106 A1 discloses an internal combustion engine with a crank case and an oil absorption case fastened to it. By means of an oil pump with two pump stages, in a first pump stage, oil to be used is fed forward for consumption into a first oil collection chamber, while in a second pump stage, oil to be used is fed directly into the first oil collection chamber from a second, rear oil collection chamber. FIG. 3 of German publication DE 101 59 106 A1 shows a lubricant which is fed through the first pump stage for consumption, cleaned by an oil filter, and cooled by an oil cooler.

This oil cooler presents hydraulic resistance which, with low oil temperatures, leads to a corresponding decrease in pressure. Flow-operated consumption, for example by hydraulically-adjustable cam shaft plates or a hydraulically-operated valve hub switch, however, cannot be adversely affected on the basis of insufficient oil pressure or quantity.

It is an object of this invention to provide a way to avoid such disadvantages.

According to the invention, in a mechanism of the sort mentioned initially, the oil cooler is integrated in the lubricant circulation of the second oil pump.

The substantial hydraulic resistance of the oil cooler is removed from the main oil circulation and integrated into the second, rear pump stage, and the lubricant supply to consumers can be improved. Apart from a better lubricant supply to the principle consumer, the input of both oil pumps can be reduced, in sum, if, by way of the second pump stage, a smaller oil volume stream is promoted, since, corresponding to the hydraulic resistance of the oil cooler, it is smaller.

By eliminating the oil cooler from the main supply circulation, the oil pump arranged in the main circulation stream can be designed to be smaller. The drive power of the compression phase is reduced, therefore, by the order of magnitude of the pressure loss of the oil cooler.

Advantageously, the oil cooler is arranged on the pressure side of the second oil pump.

Effective and efficient cooling results if the oil cooler is designed as an oil/water plate heat exchanger.

The two oil pumps are preferably combined into a double oil pump with two pump stages.

In an internal combustion engine with an exhaust-gas turbocharger, in which a drive assembly of the exhaust-gas supercharger is supplied with lubricant, the oil from the oil exhaust pump in the first chamber is preferably moved back and likewise can be cooled through the oil cooler. In addition, the pressure side of the exhaust pump flows upstream of the oil cooler to the auxiliary lubricant circulation of the second oil pump (second compression phase).

The invention is better explained in the following description and by referring to the drawing figure.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1, the only figure, is a schematic illustration of a hydraulic system of a loaded, double-row internal combustion engine with eight cylinders.

DETAILED DESCRIPTION OF THE INVENTION

Front and rear chambers, which are designated in the following description as a first oil collection chamber 2 a and a second oil collection chamber 2 b, feed to a crankcase (not represented) of an internal combustion engine. In the schematic representation provided, an oil receiving case takes the form of an oil pan 2.

A first intake manifold 4 is placed into the first oil collection chamber 2 a, and a second intake manifold is placed into the second oil collection chamber 2 b. The intake manifolds 4 and 6 are respectively attached to suction sides of oil pumps 8 or pump stages 10. In the embodiment illustrated, both oil pumps 8 and 10 are combined into one double oil pump with two pump stages, and the first pump stage 8 is adjustable. Lubricant that is received in the second oil collection chamber 2 b is pumped, with the help of the second pump stage 10, into the first oil collection chamber 2 a. Lubricant in a circuit leading from the second oil collection chamber 2 b circulates through an oil cooler 12, which is integrated in that circuit as a plate heat exchanger and provides for corresponding cooling of the lubricant. The actual internal combustion engine lubricant, which is contained in the first oil collection chamber 2 a, is supplied by the first pump stage 8. Oil is also supplied by the first pump stage to the following: a main bearing or bearings of a crankshaft 14, a bearing or bearings for four cam shafts 16, and piston spraying nozzles 18 (4×), as well as to intake plates of proposed hydraulically operable cam shaft adjusters or affecters 20, adjustable bucket tappets 22, valve hub switches (Porsche VarioCamPlus-System), and lateral hydraulically operable valve clearance compensating elements 24. Lubricant supplied for the cam shafts 16, the cam shaft adjusters 20, the adjustable bucket tappets 22, and the valve clearance compensating elements 24 is led back from both cylinder heads over the first return channels 26 to the first oil collection chamber 2 a, while the lubricant for the main bearing or bearings of the crankshaft 14 and the piston spraying nozzles 18 is led by the second oil return channels 28 to the second oil collection chamber 26.

Exhaust-gas turbochargers or superchargers 30 and 32 for the cylinder bank rows are likewise supplied with lubricant via the first pump stage 8 for lubrication of the drive assembly. Lubricant discharged from the exhaust-gas turbochargers 30 and 32 is suctioned by oil exhaust pumps 34 and 36 from catch tanks 38 and 40 and then reclaimed in the first oil collection chamber 2 a. Accordingly, as is evident, lubricant advancing from both of the oil exhaust pumps 34 and 36 is also cooled via the oil cooler 12. A common pressure pipe 42 additionally extends from the exhaust pumps to a pressure pipe 44 leading from the second pump stage.

A safety relief valve 46 is provided to limit the maximum oil pressure of the first pump stage 8, and releases excess oil by way of an appropriate bypass line 48 if necessary. A corresponding oil filter 50, with an excess pressure control valve, is provided for cleaning lubricant supplied to the consumer or consumers.

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof. 

1. A lubricant supply mechanism for an internal combustion engine comprising: an oil receiving pan arranged under a crankcase and constructed with first and second chambers designed for receiving exhausted oil, a first oil pump by which the oil is suctioned from the first chamber and provided to a consumer of the internal combustion engine, a second oil pump by which the oil is suctioned from the second chamber and provided to the first chamber, and an oil cooler for cooling the oil, wherein the oil cooler is integrated in an oil circuit provided by the second oil pump.
 2. The lubricant supply mechanism according to claim 1, wherein the oil cooler is arranged on a pressure side of the second oil pump.
 3. The lubricant supply mechanism according to claim 1, wherein the oil cooler is an oil/water heat exchanger having a slab design.
 4. The lubricant supply mechanism according to claim 1, wherein the first and second oil pumps are combined into a double pump with two pump stages.
 5. The lubricant supply mechanism according to claim 1, and further comprising at least one oil exhaust pump adapted to supply oil to a turbocharger or a supercharger from the first chamber, wherein the oil is returned from the turbocharger or the supercharger to the oil cooler by the at least one oil exhaust pump.
 6. The lubricant supply mechanism according to claim 1, wherein the consumer is a crankshaft bearing or a cam shaft bearing.
 7. The lubricant supply mechanism according to claim 2, wherein the oil cooler is an oil/water heat exchanger having a slab design.
 8. The lubricant supply mechanism according to claim 2, wherein the first and second oil pumps are combined into a double pump with two pump stages.
 9. The lubricant supply mechanism according to claim 3, wherein the first and second oil pumps are combined into a double pump with two pump stages.
 10. The lubricant supply mechanism according to claim 2, and further comprising at least one oil exhaust pump adapted to supply oil to a turbocharger or a supercharger from the first chamber, wherein the oil is returned from the turbocharger or the supercharger to the oil cooler by the at least one oil exhaust pump.
 11. The lubricant supply mechanism according to claim 3, and further comprising at least one oil exhaust pump adapted to supply oil to a turbocharger or a supercharger from the first chamber, wherein the oil is returned from the turbocharger or the supercharger to the oil cooler by the at least one oil exhaust pump.
 12. The lubricant supply mechanism according to claim 4, and further comprising at least one oil exhaust pump adapted to supply oil to a turbocharger or a supercharger from the first chamber, wherein the oil is returned from the turbocharger or the supercharger to the oil cooler by the at least one oil exhaust pump.
 13. The lubricant supply mechanism according to claim 6, and further comprising at least one oil exhaust pump adapted to supply oil to a turbocharger or a supercharger from the first chamber, wherein the oil is returned from the turbocharger or the supercharger to the oil cooler by the at least one oil exhaust pump. 